The type of microphones are divided mainly into capacitor and dynamic microphones. Since the dynamic microphone(s) without requirement of feeding thereto have respective large appearances, it is difficult that the foregoing dynamic microphone(s) are set so as not to attract attention and catch eyes of persons in such the facility.
On the other hand, the capacitor microphone(s) require addition of a power supply for the drive. However, the microphone(s) may be constructed in smaller designs with smaller appearance, which are preferable for avoidance of attention being attracted. Therefore, the microphone(s) are mostly used in the meeting, language laboratory (LL) facility, and so on having requirement of many small microphones.
Such the meeting or LL facility has at least one socket installed in e.g., a desk or floor for feeding to respective capacitor microphone(s). Connection of a connector of the microphone to the socket by the user establishes feeding of power to the microphone, wherein the socket has a phantom power supply having two functions of power supply to the microphone and audio signal input from the microphone to an audio console.
Thus, when the participants or students in the meeting or LL facility switch on respective microphone switches to have speaking with the microphone(s), both of phantom power supply to and audio signal output from the microphone are performed.
When the participants or students have no speaking in the facility, they switch off respective microphone switches. The microphone may have an indicator lamp, e.g. a light emitting diode which is turned to on or off in accordance with the foregoing switch-on/off by the participants or students. Such the capacitor microphone(s) may have fixable or removable setting in the meeting or LL facility. It also may have integration with a headphone.
Such the capacitor microphones to be set require the user to previously check phantom power supply which should be established between the connector(s) and socket(s). Conventionally, when the user needs to know the establishment of phantom power supply, he or she has to turn on the microphone switch after connection of the connector to the socket. This is troublesome task to the user.
In addition, if the connection of the connector of the microphone to the socket by the user is carried out at switch-on of the microphone switch, the microphone will output the produced harsh, rustling noises to the speakers, headphones, and so on, or be often damaged. As forgetting to turn off the microphone switch in meeting or LL facility will cause noises (e.g. noises of the desk, paper, and so on) around the microphone to be loudened through the speakers, headphone, and so on, it will interrupt participants or students in the meeting or class.